1. Field of the Invention
The present invention relates in general to a monitoring camera of a closed circuit television (CCTV), and more particularly to monitoring apparatus and method for the monitoring camera of the CCTV, whereby an operation of a zoom lens and upward, downward, left and right rotating operations of the monitoring camera can readily be monitored when the monitoring camera performs a monitoring function.
2. Description of the Prior Art
With reference to FIG. 1, there is shown a block diagram of conventional monitoring apparatus for a monitoring camera of a CCTV. The illustrated monitoring apparatus comprises a zoom lens controller 7 for controlling zoom-in/out of a zoom lens 1, an upward/downward rotating member 3 for rotating a monitoring camera 2 of the CCTV upwardly and downwardly, a left/right rotating member 4 for rotating the monitoring camera 2 of the CCTV to the left and right, an upward, downward, left and right rotation controller 6 for controlling upward/downward rotations of the upward/downward rotating member 3 and left/right rotations of the left/right rotating member 4, a signal processing unit 5 for processing a video signal being outputted from the monitoring camera 2, and a monitor 8 for displaying an output signal from the signal processing unit 5 on the screen.
As can be seen in FIG. 2 which is a detailed diagram of the signal processing unit 5 of FIG. 1, the signal processing unit 5 includes an input buffer 9 for inputting the video signal from the monitoring camera 2 and buffering the inputted video signal, a video amplifier 10 for amplifying an output signal from the input buffer 9 and an output buffer 11 for buffering an output signal from the video amplifier 10 and outputting the buffered signal to the monitor 8.
With reference to FIG. 3, there is shown a detailed diagram of the upward, downward, left and right rotation controller 6 in FIG. 1. As shown in this drawing, the upward, downward, left and right rotation controller 6 includes an upward/downward rotating motor 3' for rotating the upward/downward rotating member 3, an upward/downward rotating motor driver 12 for driving the upward/downward rotating motor 3', a left/right rotating motor 4' for rotating the left/right rotating member 4, a left/right rotating motor driver 13 for driving the left/right rotating motor 4', upward/downward rotating switches SW1 and SW2 for switching flow direction of an alternating current (AC) power which is supplied to the upward/downward rotating motor driver 12, in order to control the rotational direction of the upward/downward rotating motor 3', left/right rotating switches SW3 and SW4 for switching the flow direction of the AC power which is also supplied to the left/right rotating motor driver 13, in order to control the rotational direction of the left/right rotating motor 4', upward/downward rotation limited position detecting contacts 22 and 23 for detecting upward/downward rotation limited positions of the upward/downward rotating motor 3', respectively, upward/downward rotation limiting switches SW5 and SW6 for inputting rotation limited position detect signals from the upward/downward rotation limited position detecting contacts 22 and 23, as trigger signals, respectively and controlling blocking of the AC power which is supplied to the upward/downward rotating switches SW1 and SW2, in response to the inputted rotation limited position detect signals, respectively, left/right rotation limited position detecting contacts 24 and 25 for detecting left/right rotation limited positions of the left/right rotating motor 4', respectively, left/right rotation limiting switches SW7 and SW8 for inputting rotation limited position detect signals from the left/right rotation limited position detecting contacts 24 and 25, as trigger signals, respectively and controlling blocking of the AC power which is supplied to the left/right rotating switches SW3 and SW4, in response to the inputted rotation limited position detect signals, respectively, and a power control switch SW9 for controlling input of the AC power for driving the upward, downward, left and right rotations.
Also, as seen from FIGS. 4 and 6 which are a detailed diagram of the zoom lens controller 7 in FIG. 1 and a detailed circuit diagram of the zoom lens controller 7 in FIG. 4, respectively, the zoom lens controller 7 includes a zoom motor M for rotating the zoom lens 1, a clock generator 16 for generating a clock signal of desired frequency, a frequency divider 15 for frequency-dividing an output signal from the clock generator 16 by a predetermined period, a zoom motor driver 14 for driving the zoom motor M in response to an output signal from the frequency divider 15, zoom buttons PB1 and PB2 for outputting zoom-in/out control signals in accordance with a selection of the user such that the output signal from the frequency divider 15 being applied to the zoom motor driver 14 is switched to control rotating direction of the zoom motor M, zooming limited position detecting contacts 20 and 21 for detecting zooming limited positions, or rotation limited positions of the zoom motor M, respectively, and zooming limiting switches SW10 and SW11 for inputting zooming limited position detect signals from the zooming limited position detecting contacts 20 and 21, as trigger signals, respectively, and controlling a direct current (DC) power Vcc which is supplied to the zoom buttons PB1 and PB2, in response to the inputted zooming limited position detect signals, respectively. As shown in FIG. 6, the zoom lens controller 7 is also provided with AND gates G1 and G2 for ANDing the output signal from the frequency-divider 15 and output signals from the zoom buttons PB1 and PB2, respectively. Also, AND gates G1 and G2 provide drive signals to transistor pairs Q2, Q3 and Q1, Q4, respectively, which supply current to the zoom motor M in opposite directions, such that it rotates in the normal or reverse direction.
The operation of the conventional monitoring apparatus for the monitoring camera of the CCTV with the above-mentioned construction will now be described.
Typically, in the closed circuit television (CCTV), there is provided the monitoring camera which is installed in a place to be monitored, to pick up an image of the place. The image of the monitored place picked up by the monitoring camera is watched by the user in a monitoring station through the monitor. For the purpose of monitoring the desired place in every direction, the monitoring camera 2 rotates upwardly and downwardly and to the left and right as the upward/downward rotating member 3 and the left/right rotating member 4 are rotated by the upward, downward, left and right rotation controller 6. Also, the zoom lens controller 7 is adapted to control zoom-in/out of the zoom lens 1.
When the user wishes to adjust the image pickup angle of the monitoring camera 2 upwardly and downwardly and to the left and right, he or she turns on the power control switch SW9 and then operates the upward/downward rotating switches SW1 and SW2 and the left/right rotating switches SW3 and SW4 in the upward, downward, left and right rotation controller 6 in FIG. 3. The switches SW1, SW2, SW3 and SW4 are operatively connected to one another, respectively. First, if the user operates the upward/downward rotating switches SW1 and SW2 such that their movable terminals b1 and b2 are connected respectively to their fixed terminals a1 and a2, the AC power is applied to the upward/downward rotating motor driver 12, thereby causing the upward/downward rotating motor 3' to rotate the monitoring camera 2 upwardly at a desired angle. On the contrary, if the user operates the upward/downward rotating switches SW1 and SW2 such that their movable terminals b1 and b2 are connected respectively to their other fixed terminals c1 and c2, the AC power is applied to the upward/downward rotating motor driver 12, thereby causing the upward/downward rotating motor 3' to rotate the monitoring camera 2 downwardly at a desired angle.
At that time that the user operates the upward/downward rotating switches SW1 and SW2 such that the monitoring camera 2 continues to rotate in a single direction, the upward/downward rotation limited position detecting contacts 22 and 23 detect upward/downward rotation limited positions of the upward/downward rotating motor 3', respectively. Namely, as shown in FIGS. 5A and 5B, as the upward/downward rotating member 3 is rotated by the rotation of the upward/downward rotating motor 3', a rotating needle 18 rotates which is operatively connected to a center axis of rotation of the upward/downward rotating member 3. This rotation of the rotating needle 18 results in its contact with the upward or downward rotation limited position detecting contact 22 or 23 which are mounted respectively on the upward/downward rotation limited positions. Upon contact with the rotating needle 18, the upward or downward rotation limited position detecting contact 22 or 23 outputs a rotation limited position detect signal as a trigger signal to the upward or downward rotation limiting switch SW5 or SW6. As a result, the upward or downward rotation limiting switch SW5 or SW6 is opened resulting in blocking of the AC power, thereby causing the upward/downward rotating motor 3' to be stopped.
On the other hand, when the user wishes to adjust the image pickup angle of the monitoring camera 2 to the left and right, he or she turns on the power control switch SW9 and then operates the left/right rotating switches SW3 and SW4 in the upward, downward, left and right rotation controller 6 in FIG. 3, in a similar manner to the upward and downward adjustments of the monitoring camera 2. Similarly, limits in angles of the left/right rotations of the monitoring camera 2 are controlled by the left/right rotation limiting switches SW7 and SW8 based on the detection of left/right rotation limited positions of the left/right rotating motor 4' by the left/right rotation limited position detecting contacts 24 and 25. At that time that the user does not operate the upward/downward rotating switches SW1 and SW2 and the left/right rotating switches SW3 and SW4, their movable terminals b1-b4 are respectively connected to their central fixed terminals x1-x4, resulting in blocking of the AC power.
On the other hand, the zoom lens controller 7 is adapted to control zoom-in/out of the zoom lens 1. As shown in FIGS. 4 and 6, if the user pushes the zoom button PB1, the DC power is applied to a resistor R2 and one input terminal of the AND gate G1 through the zoom button PB1. The clock signal generated from the clock generator 16 is frequency-divided by the frequency divider 15 and the frequency-divided signal from the frequency divider 15 is then applied to the other input terminal of the AND gate G1. As a result, the frequency-divided signal from the frequency divider 15 is applied to bases of transistors Q2 and Q3 in the zoom motor driver 14 through the AND gate G1. For this reason, the zoom motor M rotates in one direction, resulting in zooming of the zoom lens 1. Also, if the user pushes the zoom button PB2, the DC power is applied to the resistor R2 and one input terminal of the AND gate G2 through the zoom button PB2. Also, the frequency-divided signal from the frequency divider 15 is applied to the other input terminal of the AND gate G2. As a result, the frequency-divided signal from the frequency divider 15 is applied to bases of transistors Q1 and Q4 in the zoom motor driver 14 through the AND gate G2. For this reason, the zoom motor M rotates in the other direction, resulting in zooming of the zoom lens 1.
At that time the zoom-in/out of the zoom lens 1 is controlled by pushing of the zoom buttons PB1 and PB2 by the user, the rotation limited positions of the zoom motor M are detected by the zooming limited position detecting contacts 20 and 21 which are mounted respectively on the rotation limited positions. Upon detect of the rotation limited positions, or zooming limited positions by the zooming limited position detecting contacts 20 and 21, the zooming limiting switches SW10 and SW11 are turned off, resulting in apply of low signals to the one input terminals of the AND gates G1 and G2. These low signals to the AND gates G1 and G2 block the output of the frequency divider 15 to the AND gates G1 and G2, thereby causing the zoom motor M to be stopped.
However, the conventional monitoring apparatus for the monitoring camera of the CCTV has a disadvantage, in that it is difficult to ascertain whether the current zooming position is the zoom-in position, the zoom-out position, or the zooming limited position. Moreover, the conventional monitoring apparatus has a further disadvantage, in that it is inconvenient to use, since the user must push the upward, downward, left and right rotating switches, while watching pictures on the screen of the monitor, to confirm states of the pictures moving on the screen in order to check whether the upward, downward, left and right rotating operations of the monitoring camera are normal or not.